Your training didn't fail you. It was your lack of understanding that you can't hit everything as if it was a 90lb bag. Everyone I know has gone through this in some shape or form. I don't know anyone who hasn't made this mistake. This is an assumption that your hands will adapt, You are already punching with gloves on and with supportive tape that helps hold the punching structure. Take the gloves off and and do the same thing and all of the flaws will become evident. I'm not saying you don't understand any of this because you made this statement. "Of course it is necessary to train slowly." Only people that understand will understand this much. So I know you had enough bad punching experience to make you a believer of that. I had my share of scraped knuckles from hitting a burlap bag, and wrists that gave away upon impact. My lesson was the same as many others. Train slowly first and build up to hitting hard. Unfortunately, people who don't understand will get up there and start trying to blast away. They even do it with bags that give. I definitely wasn't able to tell from the video. It looked fairly flat to me. Circular fighting systems use punches that don't travel in a straight line., Technically the punches actually do travel in a line before impact, but the line is very small in comparison to a jab. But the majority of the punch is circular with maybe 4 to 7 inches linear movement right before impact depending on the punching technique being moved. The best way to think of it is like this picture where the bottom of the swing flattens out. This may be a better picture. The part that flattens out is the point of impact. As you ca see in the picture there is only a small part of the swing that is linear. In fighting the circular punches look like this. (This is not me by the way, but a person that trains the same system as me). People who like to throw circular punches tend to do so often and that requires some give. I'm not saying to change your product because there aren't many of us in comparison to people who like to jab everything. A circular punch would land on the side of that pad where the edge is. like a baseball swing.